Musical Sweet Spot for 3D Sound

The sound of scissors dancing around your head or a bee flying in one of
your ears and out the other. It must be 3D sound - but not just your usual
surround sound experience. When not working on space rocket propellants at
his day job at Princeton University, Lebanese born Professor Edgar Choueiri
is hard at work pushing the whole experience of listening to the next level.

Professor Choueiri explains: "Surround-sound can give you a sense of an explosion
happening at a distance, but it's not accurate. With 3D audio, I can get a
fly to go around your head or if you want to really scare somebody, you can
put a sound inside their head." He goes on "3D vision goes back to 1895, people
cracked it then. 3D audio turned out to be a much more difficult problem."

Such effects have been achieved before, but none quite so easily or commercially
viable than the technique used by the professor. A software filter based on
mathematical algorithms adjusts the crosstalk between the right and left stereo
channels to trick the brain into 'misplacing' the sound produced by the speakers.
Currently the effect is localised to one or more 'sweet spots' in front of
the speakers and it works most effectively within an anechoic (echo-less) chamber,
but it has also been demonstrated using simple wireless speakers on an ordinary
laptop.

The technique has been patented by Princeton University who have recently
teamed up with the British-based technology company, Cambridge Mechatronics,
to design a 3D sound system for 3D televisions. And already Hollywood studios
are keen to see if the technology can be applied to their own productions.